1. Field of the Invention
The invention lies in the field of strafe scoring, whereby projectiles fired by an aircraft at a ground target are scored to determine whether the target was hit, or by how far and in which direction it was missed. Also determined are the number of projectiles fired by the aircraft during a particular firing pass, and the distance from the target that the aircraft fired its last round of each pass.
2. Description of the Prior Art
Military fighter aircraft training of pilots for strafing of ground targets is conducted on what are known ad "Controlled Ranges." On these ranges, a visual target, originally a cloth banner 20-foot square, and more recently, a circular cloth target made from a used drag parachute, is hung between two poles. The pilot of the fighter aircraft under training flies down a specific approach path and fires a strafe weapon, usually either a 20-mm or a 30-mm cannon, at the target. He must normally have ceased firing at a range of 2,000 feet or more from the target.
When the 20-foot square banner was used, the number of hits on the target was determined by lowering the target and counting the number of holes made by the projectiles.
More recently, when using the drag parachute as a target, scoring the number of hits is determined by use of an acoustic scoring system. With this system, a microphone is placed directly in front of the target and the amplitude of the acoustic shock waves of the passing projectiles are measured. Each type of different projectile has its own shock wave characteristics. By knowing the characteristics, a specific amplitude for a specific miss distance was determined for each type of projectile. The acoustic scoring system counts the number of projectiles passing within a specific distance of the microphone (typically 17 feet) for each aircraft firing pass and calls these hits on the target.
The existing method of determining a cease-fire distance from the aircraft to the target is by an observer on the ground at a point 2,000 feet from the target estimating the cease-fire distance by visually watching the cessation of the smoke from the aircraft cannon.
Although prior art remote scoring systems provided a reasonable method of strafe scoring, considering existing state of the art, there remains a long standing and continuing need for a more efficient, more accurate and more simplified approach without inherent disadvantages of the present scoring system, a few of which are: the existing system only estimates hits on the target by use of but one sensor and therefore does not pinpoint the locations of hits and/or misses, nor the total rounds fired; the acoustic sensor is situated directly in front of the target and has to be protected by a berm which is subject to major damage and maintenance; and the cease-fire range is a very inaccurate visual estimation.
The present invention overcomes all the disadvantages of the existing system by providing the number of hits in any preselected target shape; by determining the number and location of the projectiles which missed the target, by placing the acoustic sensor from the center of the target area to a safe position at one side, and by providing an automatic measurement of the cease-fire distance from the aircraft to the target.
The Strafe Scoring System disclosed herein provides a new, novel, unobvious and useful approach to using strategically placed acoustic sensors and signal porcessing equipment to solve the disadvantages of the prior art.